Cycloolefin copolymer resin composition and process for preparing the same

Abstract

A cycloolefin copolymer resin composition having well-balanced transparency and impact resistance which comprises (A) a cycloolefin copolymer and (B) 1 to 100 parts by weight, per 100 parts by weight of said cycloolefin copolymer, of at least one rubber-like polymer selected from the group consisting of (B1) an aromatic vinyl-isobutylene copolymer and (B2) an aromatic vinyl-conjugated diene copolymer, wherein the difference in refractive index (nD) at 20° C. between the components (A) and (B) is at most 0.015 and the particle size of the component (B) dispersed in the component (A) is from 0.4 to 3 μm. The composition may further contain a core-shell polymer (C), whereby the impact resistance can be further improved. The composition is prepared by kneading the above components at an elevated temperature optionally in the presence of an organic peroxide.

What is claimed is:  
     
       1. A transparent cycloolefin copolymer resin composition comprising: 
       (A) a cycloolefin copolymer and (B) 1 to 100 parts by weight, per 100 parts by weight of said cycloolefin copolymer, of at least one rubber-like polymer selected from the group consisting of (B1) an aromatic vinyl-isobutylene copolymer and (B2) an aromatic vinyl-conjugated diene copolymer. wherein the difference in refractive index (nD) at 20° C. between the components (A) and (B) is at most 0.015 and the particle size of the component (B) dispersed in the component (A) is from 0.4 to 3 μm; and  
       1 to 80 parts by weight of a core-shell polymer (C) per 100 parts by weight of the component (A), wherein the difference in refractive index (nD) at 20° C. between the components (A) and (C) is at most 0.015 and the primary particle size of the component (C) is from 0.1 to 1.0 μm.  
     
     
       2. The resin composition of claim  1 , wherein said cycloolefin copolymer (A) contains 1 to 99% by weight of structural units of at least one cycloolefin, 99 to 1% by weight of structural units of at least one non-cyclic olefin and 0 to 20% by weight of structural units of other vinyl compounds having at least one double bond. 
     
     
       3. The resin composition of claim  2 , wherein said cycloolefin copolymer (A) contains 40 to 90% by weight of structural units of at least one cycloolefin and 60 to 10% by weight of structural units of at least one non-cyclic olefin. 
     
     
       4. The resin composition of any of claim  1 , wherein said aromatic vinyl-isobutylene copolymer (B1) is at least one copolymer containing at least 40% by weight of isobutylene units selected from the group consisting of styrene-isobutylene block copolymer (SIB), styrene-isobutylene-styrene block copolymer (SIBS), isobutylene-styrene-isobutylene block copolymer (IBSIB) and styrene-isobutylene random copolymer. 
     
     
       5. The resin composition of any of claim  1 , wherein said aromatic vinyl-conjugated diene copolymer (B2) is at least one member selected from the group consisting of a styrene-butadiene copolymer containing at least 40% by weight of butadiene units and a styrene-isoprene copolymer containing at least 40% by weight of isoprene units, wherein said styrene-butadiene copolymer is at least one member selected from the group consisting of a styrene-butadiene block copolymer (SB), a styrene-butadiene-styrene block copolymer (SBS) and a styrene-butadiene random copolymer (SBR), and said styrene-isoprene copolymer is at least one member selected from the group consisting of a styrene-isoprene block copolymer (SI), a styrene-isoprene-styrene block copolymer (SIS) and a styrene-isoprene random copolymer (SIR). 
     
     
       6. A process for preparing a transparent cycloolefin copolymer resin composition which comprises kneading (A) a cycloolefin copolymer and (B) 1 to 100 parts by weight, per 100 parts by weight of said cycloolefin copolymer, of at least one rubber-like polymer selected from the group consisting of (B1) an aromatic vinyl-isobutylene copolymer and (B2) an aromatic vinyl-conjugated diene copolymer in the presence of (D) 0.0001 to 6 parts by weight, per 100 parts by weight of the component (A), of an organic peroxide at a temperature of 180 to 300° C.; 
       wherein the components (A) and (B) are kneaded together with 1 to 80 parts by weight of a core-chell polymer (C) per 100 parts by weight of the component (A).  
     
     
       7. A transparent cycloolefin copolymer resin composition comprising (A) a cycloolefin copolymer and (B) 1 to 100 parts by weight of an aromatic vinyl-isobutylene copolymer per 100 parts by weight of said cycloolefin copolymer, wherein the difference in refractive index (nD) at 20° C. between the components (A) and (B) is at most 0.015 and the particle size of the component (B) dispersed in the component (A) is from 0.4 to 3 μm. 
     
     
       8. The resin composition of claim  7 , wherein said cycloolefin copolymer (A) contains 1 to 99% by weight of structural units of at least one cycloolefin, 99 to 1% by weight of structural units of at least one non-cyclic olefin and 0 to 20% by weight of structural units of other vinyl compounds having at least one double bond. 
     
     
       9. The resin composition of claim  7 , wherein said cycloolefin copolymer (A) contains 40 to 90% by weight of structural units of at least one cycloolefin and 60 to 10% by weight of structural units of at least one non-cyclic olefin. 
     
     
       10. The resin composition of claim  7 , wherein said aromatic vinyl-isobutylene copolymer (B) is at least one copolymer containing at least 40% by weight of isobutylene units selected from the group consisting of styrene-isobutylene block copolymer (SIB), styrene-isobutylene-styrene block copolymer (SIBS), isobutylene-styrene-isobutylene block copolymer (IBSIB) and styrene-isobutylene random copolymer.